A typical idle stop-and-go system is a system for improving fuel efficiency by preventing unnecessary fuel consumption, due to engine idling, by stopping an operation of an engine while a vehicle is not moving. When the vehicle stops, the idle stop-and-go system automatically stops the engine several seconds later. Subsequently, in the case that a driver's intention to drive the vehicle is detected, for example, when a brake pedal is released or a gear is changed, the system automatically restarts the engine even without operation of an ignition key.
A conventional idle stop-and-go system is controlled without considering conditions of engine state or a position of the ignition key. Therefore, in the conventional idle stop-and-go system, there is a problem that an idle stop-and-go control is not stable.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known in this country to a person of ordinary skill in the art.